The State Administration Council of Myanmar said on the 29th that the powerful earthquake that struck on the 28th had left over a thousand people dead. Moreover, parts of neighboring Thailand and Laos also felt strong tremors, with varying degrees of casualties and building collapses. Why was the earthquake in Myanmar so destructive?
The earthquake had a large magnitude, a shallow hypocenter, and numerous aftershocks. Although different international agencies have reported slightly different measurements for this earthquake in Myanmar, overall, it was shown to be a major earthquake of over magnitude 7. According to the US Geological Survey's earthquake information network, a 7.7 - magnitude earthquake hit northwestern Sagaing Region in Myanmar on the 28th, with a focal depth of 10 kilometers.
Bill McGuire, an honorary professor of geophysics and climate hazards at University College London, pointed out that this might be the largest earthquake to hit the continental area of Myanmar in over 70 years. The large magnitude and shallow depth significantly increased its destructiveness. "A fairly large aftershock has already occurred, and more are expected. This will cause some vulnerable buildings to collapse and make the work of rescue teams more challenging."
The Myanmar Department of Meteorology and Hydrology reported early on the 29th that 12 aftershocks had been detected, with the highest - magnitude aftershock reaching 7.5 and the lowest 2.8.
The Sagaing Fault is like a "powder keg". In the global geological plate system, the collision between the Indian Plate and the Eurasian Plate has formed several geological fault zones. In the area where Myanmar is located, the north - south - trending Sagaing Fault, which is 1,200 kilometers long, has been created. It slips and displaces by a few centimeters on average each year and is one of the most active faults in the world.
Historically, the Sagaing Fault has experienced multiple strong earthquakes. Since the 20th century, there have been several earthquakes of magnitude 7 or above. Data shows that the last major earthquake of magnitude 7.5 or above on the Sagaing Fault occurred in 1946, more than 70 years ago. The energy accumulated from plate movement and displacement over a long - term is like a "powder keg" that could be detonated at any time.
Michael Steckler, a geophysicist at Columbia University, explained that when the moving plates get stuck, the stress from the compression increases. "Over decades or centuries, the stress increases very slowly, and then suddenly, the rock plates jump," which triggers an earthquake.
Ion Watkinson, an expert from the Department of Earth Sciences at Royal Holloway, University of London, pointed out that the Sagaing Fault does not experience frequent earthquakes like some other faults, but when an earthquake occurs, it tends to be of a higher magnitude. These earthquakes usually have a shallow focal depth, typically around 10 to 15 kilometers, which means that the seismic energy does not dissipate much before reaching the surface.
A large number of casualties are feared. The Sagaing Fault passes through several major cities and densely populated areas in Myanmar. Important cities such as Naypyidaw and Mandalay are within its influence range. The State Administration Council of Myanmar announced that the earthquake occurred near Mandalay. Mandalay is the second - largest city in Myanmar and one of the country's economic, political, and cultural centers.
Many buildings in the affected areas have weak seismic resistance. In Mandalay, the earthquake destroyed several buildings, including one of the city's largest temples. Earthquakes caused the collapse of buildings and bridges in many places, with one bridge located on a major highway between Mandalay and Yangon.
After the earthquake, the casualty figures released by the Myanmar authorities rose rapidly. Data released by the State Administration Council of Myanmar on the 29th showed that the death toll across the country had exceeded a thousand, with 2,376 people injured, and it was indicated that the casualty figures might continue to rise.
Related projects of the US Geological Survey even predicted that there was a 60% chance that this earthquake would cause over 10,000 deaths. Brian Baptie, a seismologist at the British Geological Survey, said, "When a major earthquake occurs in an area with over a million people, many of whom live in vulnerable buildings, the consequences are often catastrophic."
The leader of Myanmar called on countries, organizations, and the public to provide assistance to the earthquake - affected areas in Myanmar. The UN Secretary - General said that the UN system was mobilizing resources to provide assistance to the affected people in Southeast Asia.
